1. Field of the Invention
The invention relates to a working machine control device for construction machinery such as a power shovel, by which a pushing force between a working plane and a working attachment can be varied as required and a working plane profiling function is realized to let the working attachment automatically follow along the working plane.
2. Description of the Related Art
Where construction machinery such as a power shovel is used to perform dusting to remove dust and trash from the ground surface or rolling compaction to compact the soft ground, the working plane profiling function is generally performed to let the working attachment automatically follow along a working plane.
The working plane profiling function is generally performed by having a boom (and an arm) in so-called floated state to passively move a working machine depending on a load.
However, the profiling control utilizing the floated state is not effective to apply a relatively large pushing force to the working plane, and the pushing force cannot be set to an arbitrary value.
The power shovel is often provided with a horizontal excavating function to level the ground. The horizontal excavating function drives the boom automatically so as to keep the arm end point or the bucket blade end point at a predetermined height in correspondence with manual operation of the arm and the bucket. Specifically, the horizontal excavating function controls to always keep the arm end point or the bucket blade end point at the same absolute height regardless of irregularities of the ground. Therefore, the horizontal excavating function cannot be used for the dusting work to remove dust and trash from the uneven ground or for the rolling compaction work.
The invention was achieved in view of the above circumstances and aims to provide a working machine control device for construction machinery, which enables to achieve working by an arbitrary pushing force.
The invention also aims to provide a working machine control device for construction machinery, which enables to achieve profiling work by an arbitrary pushing force with a relatively simple configuration without requiring delicate manipulation by an operator.